The present invention relates to a strap detector assembly for automatic strapping machines. More particularly, the present invention relates to a detector for determining whether strapping material is properly positioned around and sealed to a load.
Strapping machines are typically used to strap articles or a load together. There are two principal types of strapping machines known in the art: (1) manual strapping machines; and (2) automatic strapping machines.
One type of automatic strapping machine includes a frame-like support for the overall machine, a strapping head, a chute around which the strap is fed and one or more dispensers for dispensing the strap material to the strapping head.
The strapping head moves toward the load, pulls the strap material from the dispensers, and conveys the strapping material to a first end of the chute until a leading portion of the strap returns to the strapping head. At the strapping head, the leading portion or leading end is gripped and the trailing portion or end of the strap is retracted and tensioned to provide an appropriate compression on the strapped load. The strap is then sealed to itself in an overlapping manner, the trailing end portion is severed and the load removed from the machine. The strapping head moves away from the load after each strapping operation has been completed. This process can be repeated for an extended period of time with very little human intervention.
However, occasionally, while the automatic strapping machine is operating without human intervention, the strapping material is improperly sealed around the load. In these circumstances, an improperly secured load results which can result in load tipping and spillage. This can result in the loss of load and labor resources. It would be impractical in terms of both man-hours and strapping operation time to require an employee to supervise automatic strapping machine operations.
Accordingly, there continues to be a need for an automatic strapping machine, or a device to be used with an automatic strapping machine, that ensures that strapping material is properly sealed around a load, thus facilitating a properly secured load.
The present invention relates to an automatic strapping machine configured to strap articles together by conveying strapping material into a first end of a chute. The strapping material exits the chute at a second end and is sealed to itself at a strapping head. The strapping head moves away from the articles after forming a seal and toward the articles to form the seal.
The automatic strapping machine comprises the strapping head and a strap detector mounting bracket mounted to the automatic strapping machine. In one embodiment, the strap detector mounting bracket can be mounted to the strapping head.
A pivot block can be attached to the mounting bracket, and the pivot block can have an aperture formed therein. A shaft can be positioned in the pivot block aperture, and a finger can be mounted to the shaft at a free end. A sensed element, such as a guide block, can be positioned along the shaft spaced from the free end.
A proximity sensor can be operatively coupled to the detector mounting bracket proximal the guide block. The finger can be engaged by sealed strapping material during a strapping operation and, if the strapping material is properly sealed to itself movement of the strapping head away from the articles moves the guide block into a position to change a state of the sensor.
The automatic strapping machine can further include a notification device. The notification device can be actuated if the sensor state does not change after the strapping head moves away from the articles. Preferably, the notification device disables the strapping machine when it is actuated.
The automatic strapping machine can also include a biasing element positioned along the shaft, and positioned between the guide block and the pivot block. In one embodiment, the biasing element is a spring.
In one embodiment, the sensor is operatively coupled to the detector mounting bracket by the sensor support bracket. Preferably, an elongated slot is formed within the sensor support bracket and the sensor is connected to the sensor support at the elongated slot. Thus, the elongated slot allows for sensor position adjustment.
The guide block can include a guide attached to a bottom surface of the guide block and a cam groove can be formed within the detector mounting bracket. The cam groove and guide can be configured to cooperate with one another. The guide can be a bearing, and the sensor can be a proximity sensor.
Other features and advantages of the present invention will be apparent from the following detailed description, the accompanying drawings, and the appended claims.